WS2801 Pixel Protocol
Manufacturer: WorldsemiA two-wire clocked RGB LED driver with an integrated controller and 8-bit-per-channel colour, using separate data and clock lines for timing-tolerant control.
Specifications
| Specification | Detail |
|---|---|
| Clock Type | Clocked |
| Color Resolution | 8 Bits |
| Physical Package | SOP14 |
| RGB | Yes |
| RGBW | No |
| Output Pixel Voltage | 5V |
| PWM Rate | 2500Hz |
| Suitable Camera | Up to 84fps |
| Redundant Data Line | No |
Strengths
- Two-wire clocked control latches data on the shared clock line rather than on strict bit timing, so the WS2801 tolerates slower or less precise controllers and long, electrically noisy runs.
- 8-bit-per-channel RGB (24-bit colour) in a compact SOP14 package gives standard, predictable colour mixing across a pixel string.
- The 2500Hz PWM rate is comfortably flicker-free for the rated cameras up to 84fps, so on-camera installs read clean without visible banding from the refresh.
Limitations
- Being clocked, it needs a second (clock) conductor: that adds wiring and cost, another connection that can fail, and a high-frequency clock line that radiates EMI and can interfere in sensitive installs. The market has largely moved to data-only single-wire chips to avoid both, so the timing tolerance is a genuine but costly tradeoff, not simply 'better'.
- Colour resolution is 8 bits per channel (256 levels), so deep fades and low-level dimming can show visible stepping compared with higher-bit-depth drivers.
- It is RGB only with no white channel and carries no redundant data line, so a single break in the chain stops all downstream pixels. At 5V, voltage drop also limits practical run length before power injection is needed.
Overview
The WS2801 is a three-channel constant-current LED driver that runs on a two-wire clocked interface: a dedicated DATA line alongside a separate CLOCK line, rather than the self-clocking single-wire scheme of chips like the WS2812. Each 5V device stores 24-bit RGB (8 bits per channel) and cascades data down the chain. Because the receiver latches on the shared clock instead of on tight bit timing, the WS2801 tolerates slower or less precise drivers, which historically made it forgiving to control. Its 2500Hz PWM keeps output comfortably flicker-free for camera work up to 84fps. ENTTEC is not affiliated with Worldsemi.
Mapping an installation? ELM, ENTTEC's free LED pixel mapping software, drives the controllers above over Art-Net and sACN, from a single fixture to building-scale maps.
ENTTEC has been engineering lighting control in Australia since 1999, and shipping LED pixel controllers since the original Pixelator in 2014.